Я не думаю, что у нас есть подтаблицы. но из вашей проблемы звучит как нормальные отношения?
create table restaurant as
select 1 AS restaurant_ID, 'Nandos' AS restaurant_name
union
select 2, 'Frankie';
create table staff as
select 1 AS staff_ID, 'Andrew' AS staff_name
union
select 2, 'Crossan';
create table menu as
select 1 AS menu_ID, 'Burger' AS menu_name
union
select 2, 'Sandwich';
create table order_history as
select 1 AS order_ID, 1 AS restaurant_ID, 1 AS staff_ID, 1 AS menu_ID, 1 AS qty, 12 AS price # 1 qty of Burger served by Andrew on Nandos restaurant
union
select 1, 1, 1, 2, 3, 8; #3 qty of Sandwich served by Andrew on Nandos restaurant
теперь попробуйте выбрать из order_history, присоединяясь к другим таблицам